1. Field of the Invention
This invention relates to storage systems, and more specifically to data recovery storage systems that improve the data access speed after a failure occurs by automatically recovering a volume from a replicated volume and switching a data access path to the new volume.
2. Description of the Related Art
Storage area networks (SAN) provide a solution for storing and retrieving mass amounts of data. A typical SAN architecture may include one or more host devices interconnected to one or more network devices or switches through an interface. The network devices or switches may then be interconnected to one or more data storage devices through a second network or interface. Many SAN architectures use Fibre Channel (FC) as the interface or network, however, Ethernet, Infiniband, Internet, and other networks/interfaces may also be used in a SAN architecture.
Since the amount of important data stored in storage systems is always increasing, the storage systems have to be more reliable. However, even if new technologies are developed for better reliability, the failure of storage systems is still possible. Even worse, currently the possibilities of disasters are rising. To protect data stored in storage systems, the backup and recovery mechanisms become important. Further, the high availability parts of storage systems are crucial in order to keep the storage systems available even if a failure occurs.
A local replication mechanism usually uses a local volume as a replication target. In order to reduce the risk of disaster or failure and to reduce the cost of hardware, using a cheap or residual remote volume as a target volume is a possible solution. However, when a failure occurs and the replicated volume has to be accessed from a host, the data access speed of the replicated volume is slower than that of local volume.
Moreover, a path switch mechanism changes a data access path to a backup path if a failure of a main path is detected. Even if it works with the local replication mechanism stated above, a recovery of the replicated data is out of scope. After finishing a path switch, a recovery of data is needed in order to keep the data backup available. In current systems, the recovery process has to be manually done by users or administrators of storage systems.
Therefore, there is a need for data recovery storage systems that recover automatically and with improved data access speed after a failure occurs.